Prior art power transmissions utilizing continuously variable friction drives, such as V-belt drives, in parallel with a chain or other fixed ratio drive, to provide a geared neutral transmission are well-known. Such a transmission is shown in British Pat. No. 2,045,368 published Dec. 8, 1982. In such transmissions, the fixed ratio drive is drivingly connected between the input and one planetary gear member while the variable ratio friction drive is drivingly connected between the input and another member of the planetary gear set. The third member of the planetary gear set drives the transmission output.
It is well-known that controlling the relative speeds of the members of a planetary gear set can result in zero output speed while the other two members of the planetary gear set are rotating. Hence, the planetary is in neutral, thus the term "geared neutral".
In the prior art transmissions, the fixed ratio mechanism has been constructed to be continuously drivingly connected to the planetary gear set. Thus, the fixed ratio mechanism is continuously rotating during all phases of operation. Such rotation causes a reduction in overall transmission efficiency and an increase in system noise.